Effects of presentation mode and repeated familiarization on intelligibility of dysarthric speech.

Clinical measures of speech intelligibility are widely used as one means of characterizing the speech of individuals with dysarthria. Many variables associated with both the speaker and the listener contribute to what is actually measured as intelligibility. The present study explored the effects of presentation modality (audiovisual vs. audio-only information) and the effects of speaker-specific familiarization across 4 trials on the intelligibility of speakers with mild and severe dysarthria associated with cerebral palsy. Results revealed that audiovisual information did not enhance intelligibility relative to audio-only information for 4 of the 5 speakers studied. The one speaker whose intelligibility increased when audiovisual information was presented had the most severe dysarthria and concomitant motor impairments. Results for speakerspecific repeated familiarization were relatively homogeneous across speakers, demonstrating significant intelligibility score improvements across 4 trials and, in particular, a significant improvement in intelligibility between the 1st and 4th trials.